预压岩杆轴向卸载实验及其在研究生创新教学中的应用

Axial Unloading Experiment of Preloaded Rock and Its Application in Postgraduate Innovation Teaching

通过自制实验设备,建立了预压力岩杆轴向卸载实验平台,以及此平台在研究生创新实践教学中的应用。依据深部工程岩体的开挖卸载问题,实验中设计了横向滑移、压溃与爆破破碎三种卸载实验,确定了爆破冲击荷载与预压岩杆卸荷时长与曲线形态,得到了爆破冲击荷载与预压荷载的卸载应变率范围;借助实验平台,实现了深部岩体爆破开挖荷载中爆破荷载曲线与初始应力卸载曲线分离,为研究深部岩体爆破开挖的损伤机制奠定了基础;通过节理岩体的卸载实验明确卸载应力波的传播规律以及应变能转化为动能的演化过程。利用实验平台对研究生进行教学与训练,不仅锻炼了研究生的实际动手能力,也增强了从实验力学现象探求事物基本规律的理解能力。

In this paper,an experimental platform for axial unloading of pre-stressed rock bar is established through self-made experimental equipment,and the application of this platform in postgraduates'innovative practice teaching is also presented.According to the excavation unloading problems of deep rock mass,three unloading methods of the horizontal slip,crushing and blasting are designed,which determines the length and curve shape of blasting loading and unloading on rock bar,including the range of blasting impact loading and strain rate range of unloading.Through experimental platform,the blasting load curve and the initial stress unloading curve are separated,which is the foundation research for the damage mechanism on the blasting excavation of deep rock mass.By using this platform,the stress wave propagation and evolution of strain energy into kinetic energy are revealed with the unloading test of jointed rock mass.Finally,with the experimental platform,not only the postgraduates'practical operation ability,but also their understanding and analytical ability from experimental mechanical phenomena are enhanced through the teaching and training.